evo boy Posted February 23, 2018 Report Share Posted February 23, 2018 Hello all. I'm new to twinshocks and need some help. I have a Bultaco 325 which I think is a 1978. I'm going to change the clutch and change the oils. I've been told there is a clutch/primary oil and then a gearbox oil? Could anyone tell me what oil to use in both and how much it takes. Many thanks Quote Link to comment Share on other sites More sharing options...
woody Posted February 24, 2018 Report Share Posted February 24, 2018 Gearbox is 600cc of light gear oil such as Silkolene light or other brand equivalent If the clutch is original then the plates are all steel so you can use Auto Transmission Fluid. If the friction plates have been replaced with fibre plates then you can use ATF or light gear oil - 300cc. If you don't know whether the plates have been replaced just use ATF as it will work with either Quote Link to comment Share on other sites More sharing options...
evo boy Posted February 24, 2018 Author Report Share Posted February 24, 2018 6 hours ago, woody said: Gearbox is 600cc of light gear oil such as Silkolene light or other brand equivalent If the clutch is original then the plates are all steel so you can use Auto Transmission Fluid. If the friction plates have been replaced with fibre plates then you can use ATF or light gear oil - 300cc. If you don't know whether the plates have been replaced just use ATF as it will work with either Thanks Woody thats Great. I'm changing the clutch to a Fibre plate one because I was told you get better feel as I'm struggling if I have to touch it. Would you know what the clutch is like to change? I've done road bike ones. Many thanks Quote Link to comment Share on other sites More sharing options...
woody Posted February 24, 2018 Report Share Posted February 24, 2018 2 hours ago, evo boy said: Thanks Woody thats Great. I'm changing the clutch to a Fibre plate one because I was told you get better feel as I'm struggling if I have to touch it. Would you know what the clutch is like to change? I've done road bike ones. Many thanks Changing is easy, drain oil, cover off and remove the springs which will be held in by nuts on your bike, not pins like earlier models. Fibre plates are obviously thicker than steel so I don't think you will get the same number of fibre plates in as steel. I use Barnett friction plates which are Kevlar and I replace 1 Kevlar plate with a steel plate to get the right pack thickness. I guess it will be the same for the other types of fibre plate. The Kevlar plates break very well when the clutch is disengaged, take up is predictable and because the Kevlar bites better than the steel the spring tension can be backed off more for a lighter pull (together with using the longer front brake arm on the clutch as they are the same spline) The spring nuts are quite deep so if you back them off too much they will foul the inside of the case and make a mess. I reduce the depth of mine to avoid that. Search this forum for 'clutch set up' or such like as there are a few posts on setting the clutch up for best operation going back over the years 5 Quote Link to comment Share on other sites More sharing options...
evo boy Posted January 5, 2019 Author Report Share Posted January 5, 2019 Just about to change my oils you say ATF would AFT Dextron 3 be the right one to use and Light gear oil 75w? Thanks Quote Link to comment Share on other sites More sharing options...
model80 Posted January 10, 2019 Report Share Posted January 10, 2019 I recall that the factory use to specify 600cc of SAE 140 for the Gearbox and 250cc of 30w for the Clutch. Quote Link to comment Share on other sites More sharing options...
section swept Posted January 10, 2019 Report Share Posted January 10, 2019 Before you change from the all steel to Kevlar make sure the clutch pivot shaft is working smoothly in its housing. It only takes a few minutes to pull the shaft out and clean the shaft hole and the shaft of any burrs and corrrosion. I use a ceramic lubricant in this area and make a sealing cap for the top of the shaft housing. With careful routing of the cable, no tight bends or kinks and a well lubed cable inner and careful adjustment of the clutch pack...all springs exerting equal pressure and the operating arm set correctly so it pulls through 90 degrees and not starting at 90 degrees giving you full leverage. ATF or as I use Mercedes Benz Auto Fluid in the clutch casing you should have a clutch that works easily and disengages smoothly with out dragging like a lot of them which is usally due to set up. Enjoy which ever route you go. Quote Link to comment Share on other sites More sharing options...
evo boy Posted February 26, 2019 Author Report Share Posted February 26, 2019 On 2/24/2018 at 10:19 AM, woody said: Changing is easy, drain oil, cover off and remove the springs which will be held in by nuts on your bike, not pins like earlier models. Fibre plates are obviously thicker than steel so I don't think you will get the same number of fibre plates in as steel. I use Barnett friction plates which are Kevlar and I replace 1 Kevlar plate with a steel plate to get the right pack thickness. I guess it will be the same for the other types of fibre plate. The Kevlar plates break very well when the clutch is disengaged, take up is predictable and because the Kevlar bites better than the steel the spring tension can be backed off more for a lighter pull (together with using the longer front brake arm on the clutch as they are the same spline) The spring nuts are quite deep so if you back them off too much they will foul the inside of the case and make a mess. I reduce the depth of mine to avoid that. Search this forum for 'clutch set up' or such like as there are a few posts on setting the clutch up for best operation going back over the years Hello woody. Ive fitted the modern clutch to my 325 sherpa but having problems with the clutch ie the bit is right at the end and if you try and start it 90% of the time it's like the clutch is engaged. Once running clutch feels good works well just can't adjust to biting point at all. Would you have any ideas? Many thanks Quote Link to comment Share on other sites More sharing options...
bullylover Posted February 27, 2019 Report Share Posted February 27, 2019 If you open the round plastic cover in the middle of the primary case you will find a 21mm or 13/16ths size nut which is locking a large flat blade screw. Back the lock nut off and adjust the screw to suit you. Just tighten until it just hits and then just back it off a fraction. Tighten it all up again and away you go. Give that a go. Graham. 1 Quote Link to comment Share on other sites More sharing options...
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